Today's Message Index:
----------------------
1. 05:47 AM - Re: Alternate Fuel for 914 (Catz631@aol.com)
2. 06:25 AM - reverse prop rotation at shut down (Catz631@aol.com)
3. 08:04 AM - Re: reverse prop rotation at shut down (Robert Borger)
4. 08:10 AM - Re: reverse prop rotation at shut down (FLYaDIVE)
5. 09:28 AM - Re: reverse prop rotation at shut down (Brian Davies)
6. 05:50 PM - Re: reverse prop rotation at shut down (Alan Carter)
Message 1
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| Subject: | Re: Alternate Fuel for 914 |
Alan,
I must say that you have a pretty good handle on the Rotax engine ! When
they run,they run good but they sure take a lot of attention ! I have
worked on my engine more than any Cont/Lyc I have owned and I have owned a lot
!
(14 planes)
Good luck to you !
Dick Maddux
912 UL
PS; but I still like it
Message 2
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| Subject: | reverse prop rotation at shut down |
I didn't know quite what to call this. As many of you know I have had a on
going problem with the prop rotating backwards at shut down sometimes. It's
not really diseling (I don' think) ..Maybe it stops at the top of the pawl
in the gearbox and flips backwards. I don't know. I have had the carbs
redone ,gearbox rebuilt,prop replaced,borescoped cylinders,etc.
The only thing that appears to stop this from happening is to pull the
throttle back to about 1200 rpm (or much less) at shutdown.
Anyway, my question revolves around the possibility of ingesting air into
the lifters. My prop has gone around as much as 3 revolutions in reverse
direction. So in each case I have done the lifter check making sure I have
no more than .020 clearance between the push rods and the rocker arm (per
the service inst)
I have done this so many times that I am seriously considering attaching
my cowl with Velcro !
At no time have the clearances on the valves exceeded the parameter.
I highly suspect that rotating you prop backwards,providing there are no
open oil lines,etc is not the big deal that Rotax makes it out to be.
Obviously I am not going to do it on purpose but 3 full revolutions backward and
no air ingestion ? On at least 10 occasions ?
Stupid engine !..but it really does run well other than this quirk,it
starts at one blade,smooth... it's just perplexing.
Dick Maddux
912
UL
Message 3
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| Subject: | Re: reverse prop rotation at shut down |
Hi Dick,
I notice that you say: "The only thing that appears to stop this from happening
is to pull the throttle back to about 1200 rpm (or much less) at shutdown." That's
exactly how I shut my engine down. I let it idle at 1800-2000 RPM for a
bit to cool the turbo and just kind of quiet things down. Then for shutdown
I pull the throttle all the way back, let the engine drop to about 1200 RPM and
as it hits that 1200 I kill both ignition switches to stop. That's the only
time I let the RPM go below 1800.
Some folks may ask why I even have the throttle set to allow RPM below 1800. Good
question. I had it set that way originally and found out that the darn airplane
(as a monowheel) didn't want to come down or land with that much power
being made. I could slow-flight a thousand feet down the runway in ground effect
at 1800 RPM before it'd settle in. So I set the throttle to allow me retard
it below that 1800 idle on final approach. Then, with the throttle fully back,
the aircraft descended nicely showing 1800 RPM (rather than 2100 at the previous
setting) and at the flare I bump the throttle to keep the RPM at a satisfactory
level and I could land without coasting the full length of the runway.
Things appear to have changed a bit now that it's a tri-gear. I have to fly
it a bit more to see just how it has changed.
Blue skies & tailwinds,
Bob Borger
Europa XS Tri, Rotax 914, Airmaster C/S Prop.
Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP
3705 Lynchburg Dr.
Corinth, TX 76208-5331
Cel: 817-992-1117
rlborger@mac.com
On Jan 20, 2013, at 8:24 AM, Catz631@aol.com wrote:
I didn't know quite what to call this. As many of you know I have had a on going
problem with the prop rotating backwards at shut down sometimes. It's not really
diseling (I don' think) ..Maybe it stops at the top of the pawl in the gearbox
and flips backwards. I don't know. I have had the carbs redone ,gearbox
rebuilt,prop replaced,borescoped cylinders,etc.
The only thing that appears to stop this from happening is to pull the throttle
back to about 1200 rpm (or much less) at shutdown.
Anyway, my question revolves around the possibility of ingesting air into the
lifters. My prop has gone around as much as 3 revolutions in reverse direction.
So in each case I have done the lifter check making sure I have no more than
.020 clearance between the push rods and the rocker arm (per the service inst)
I have done this so many times that I am seriously considering attaching my cowl
with Velcro !
At no time have the clearances on the valves exceeded the parameter.
I highly suspect that rotating you prop backwards,providing there are no open
oil lines,etc is not the big deal that Rotax makes it out to be. Obviously I am
not going to do it on purpose but 3 full revolutions backward and no air ingestion
? On at least 10 occasions ?
Stupid engine !..but it really does run well other than this quirk,it starts at
one blade,smooth... it's just perplexing.
Dick Maddux
912 UL
Message 4
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| Subject: | Re: reverse prop rotation at shut down |
Guys:
I am on the Rotax list because I am very interested in getting a Ch-601 and
many of them have Rotax engines. I would jump at the chance of getting one
with a O-200 or O-235. I just can not justify in the slightest a Rotax
engine, because of issues like Dick is reporting. I may be forced into a
Rotax, only to swap it out.
But, Dick, I think I have a suggestion that may help in your situation.
Set the engine at high idle - KILL the MAG/Spark first - Then the fuel.
If the problem still occurs then look at the possibility of a Hot Spot
(Pre-Ignition)
Jerking an engine in the reverse direction is not a good thing no matter
how you look at it. Not even good for the airframe.
Barry
On Sun, Jan 20, 2013 at 9:24 AM, <Catz631@aol.com> wrote:
> **
> I didn't know quite what to call this. As many of you know I have had a on
> going problem with the prop rotating backwards at shut down sometimes. It's
> not really diseling (I don' think) ..Maybe it stops at the top of the pawl
> in the gearbox and flips backwards. I don't know. I have had the carbs
> redone ,gearbox rebuilt,prop replaced,borescoped cylinders,etc.
> The only thing that appears to stop this from happening is to pull the
> throttle back to about 1200 rpm (or much less) at shutdown.
> Anyway, my question revolves around the possibility of ingesting air into
> the lifters. My prop has gone around as much as 3 revolutions in reverse
> direction. So in each case I have done the lifter check making sure I have
> no more than .020 clearance between the push rods and the rocker arm (per
> the service inst)
> I have done this so many times that I am seriously considering attaching
> my cowl with Velcro !
> At no time have the clearances on the valves exceeded the parameter.
> I highly suspect that rotating you prop backwards,providing there are no
> open oil lines,etc is not the big deal that Rotax makes it out to be.
> Obviously I am not going to do it on purpose but 3 full revolutions
> backward and no air ingestion ? On at least 10 occasions ?
> Stupid engine !..but it really does run well other than this quirk,it
> starts at one blade,smooth... it's just perplexing.
>
> Dick Maddux
> 912
> UL
>
> *
>
> *
>
>
Message 5
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| Subject: | reverse prop rotation at shut down |
Barry,
If you treat a Rotax like a Lyc/Cont it will protest. Switching off the
ignition at high idle will cause the problem being described. I was taught
to close the throttle completely and then switch off one mag, and then both
mags. That way the engine stops without kick back. The gearbox arrangement
prevents the engine stopping softly like a Lycoming. It will always stop
suddenly as if it has seized. Once you get used to it, it will not give you
any problems.
Regards
Brian
From: owner-rotaxengines-list-server@matronics.com
[mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of FLYaDIVE
Sent: 20 January 2013 16:10
Subject: Re: RotaxEngines-List: reverse prop rotation at shut down
Guys:
I am on the Rotax list because I am very interested in getting a Ch-601 and
many of them have Rotax engines. I would jump at the chance of getting one
with a O-200 or O-235. I just can not justify in the slightest a Rotax
engine, because of issues like Dick is reporting. I may be forced into a
Rotax, only to swap it out.
But, Dick, I think I have a suggestion that may help in your situation. Set
the engine at high idle - KILL the MAG/Spark first - Then the fuel. If the
problem still occurs then look at the possibility of a Hot Spot
(Pre-Ignition)
Jerking an engine in the reverse direction is not a good thing no matter how
you look at it. Not even good for the airframe.
Barry
On Sun, Jan 20, 2013 at 9:24 AM, <Catz631@aol.com> wrote:
I didn't know quite what to call this. As many of you know I have had a on
going problem with the prop rotating backwards at shut down sometimes. It's
not really diseling (I don' think) ..Maybe it stops at the top of the pawl
in the gearbox and flips backwards. I don't know. I have had the carbs
redone ,gearbox rebuilt,prop replaced,borescoped cylinders,etc.
The only thing that appears to stop this from happening is to pull the
throttle back to about 1200 rpm (or much less) at shutdown.
Anyway, my question revolves around the possibility of ingesting air into
the lifters. My prop has gone around as much as 3 revolutions in reverse
direction. So in each case I have done the lifter check making sure I have
no more than .020 clearance between the push rods and the rocker arm (per
the service inst)
I have done this so many times that I am seriously considering attaching my
cowl with Velcro !
At no time have the clearances on the valves exceeded the parameter.
I highly suspect that rotating you prop backwards,providing there are no
open oil lines,etc is not the big deal that Rotax makes it out to be.
Obviously I am not going to do it on purpose but 3 full revolutions backward
and no air ingestion ? On at least 10 occasions ?
Stupid engine !..but it really does run well other than this quirk,it
starts at one blade,smooth... it's just perplexing.
Dick
Maddux
912
UL
ist" target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
No virus found in this message.
Checked by AVG - www.avg.com
Message 6
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| Subject: | Re: reverse prop rotation at shut down |
Hi all.
It does seem to have a lot of problems Staring and Stopping, seems more have problems
than don,t.
The design, the prop coming to a sudden stop, which is normal for the Rotax engine,
so it may be, but my common scene tells me it not an ideal way an engine
should stop,
I run my engine for 3 minutes at idle to cool the turbo down, and stop it at the
lowest RPMs i can achieve.
Your problem sound like Pre ignition the engine it hot.
My starting Kick back is Detonation of the fuel, or the timing to far in advance
and the piston not getting over TDC.
During crank at starter speed i can not see to much hot air being made.
Only me making it,saying Stupid engine.
My Prop is a PV 50
Just found the receipt for the battery, 22/09/2009
ODYSSEY EXTREME RACING BATTERY 25 (16 APP/HRS-680 AMPS CRANK) priced 100 now is
that a good battery ?? it seems to turn it over OK ?
What you need is the old model aeroplane starter clipped to the spinner then the
little engine had no choice which way it was going to go, Remember those days,
or perhaps its just us old boys that made models on the end of a wire.
I would guess my plane has the standard fitted starter motor.
When i get round to it i will fit a soft start but for me it means fitting a starter
button.
Alan
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http://forums.matronics.com/viewtopic.php?p=392781#392781
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